Mass and energy limit of isotope identification of heavy ions using ΔE-E silicon-detector telescope

The technical limit of isotope identification of ions heavier than iron using a ΔE-E silicon detector telescope is presented. The identification of iron or heavier ions with energies less than 30 MeV/n is limited by the nonuniformity of the thickness in a thin silicon detector, and a decrease in the effective charge of low-velocity ions passing through a silicon medium. In an energy region higher than 300 MeV/n, the slope of the stopping power for heavy ions becomes smaller, which limits the capability of isotope identification. In the intermediate energy range, some ions heavier than iron can be identified with a resolution of σm = 0.22 amu; the maximum mass identifiable in this ΔE-E algorithm is about 100 amu because of the restriction of the nonuniformity of detector thickness and the straggling of the energy loss of ions passing through a silicon detector. (author)